Photosynthesis Objective 1 • To trace the primary food source in a food chain to the green plant The Primary Food Source • Green plants always found at the beginning of the food chain. • Why? • The only organisms that can produce their own food • They are called producers Objective 2 • To define photosynthesis PHOTOSYNTHESIS •Photo = light •Synthesis = building up DEFINITION Pho to s ynthe s is Process by which plants use wate r & c arbo n dio xide to make c arbo hydrate s in the presence of lig ht and c hlo ro phyll. Oxyg e n is given off during the process. Objective 3 • To understand the conditions necessary for plants to make their own food INTRODUCTION What are the similarities betweenYummy!!! baking a cake and photosynthesis? REQUIREMENTS •Rawmaterials –Carbon dioxide –Water •Conditions –Chlorophyll –Light energy Answers • Review 1 1. An organism that make its own food, e.g. green plant 2. They make their own food by photosynthesis • Review 2 1. Textbook pg 19 • Review 3 – – – Raw materials: water & carbon dioxide Conditions: sunlight & chlorophyll End products: oxygen & glucose Objective 4 • To outline the process of photosynthesis by which plants manufacture carbohydrates using raw materials • To state that food is stored as starch in the plant CARBON DIOXIDE •From air •Enters leaf by diffusion •Pores: Stomata/Stoma •Found underside of the leaf Carbon dioxide WATER •From soil •Absorb by root hair •Enter by osmosis •Transport by xylem vessel To Xylem Vessel Soil Water Root Hair Water Water Water CHLOROPHYLL •Structure: Chloroplast •Green pigment: Chlorophyll •Absorb light energy Plant Cell Chloroplast Leaf LIGHT ENERGY • Chlorophyll absorbs light energy from sun • Light energy converted into chemical energy • Chemical energy is needed to convert carbon dioxide to carbohydrate • Series of chemical reactions CO2 H2O H2O Xylem H2O CO2 Surroundings O2 O2 Light Carbon Dioxide +Water Chlorophyll Glucose STARCH+ Oxygen WORD EQUATION CARBON DIOXIDE + WATER LIGHT ENERGY GLUCOSE + OXYGEN CHLOROPHYLL Review 4 1. 2. 3. 4. 5. 6. 7. 8. Water, carbon dioxide, sunlight Chlorophyll It absorb the sunlight/light energy Chloroplasts The root hair absorb the water by osmosis Xylem vessel It enters through the stomata by diffusion Carbon dioxide + water Light energy glucose + Chlorophyll oxygen Objective 5 • To state the conditions that affect the rate of photosynthesis LIMITING FACTORS • Rate of photosynthesis is affected by: –carbon dioxide, –light intensity and –temperature LIGHT INTENSITY • Higher light intensity, faster the rate of photosynthesis • After awhile, the rate will remain constant • Due to limiting factors such carbon dioxide concentration or temperature CARBON DIOXIDE • Carbon dioxide in the air is 0.03% • Increasing the carbon dioxide concentration to 0.1% increases the rate of photosynthesis • After awhile the rate will remain constant due to limiting factor such as temperature and light intensity TEMPERATURE • Temperatures below40°C, as it rises, the rate of photosynthesis is faster • At 40°C, photosynthesis begins to decrease • As temperature rises above 40°C, photosynthesis stop as the enzymes denatured Other important things that plant need to grow • Minerals – Found in soil and fertilizers – Magnesium: chlorophyll formation – Nitrogen: for making proteins Objective 6 • To compare the conditions for healthy growth of ornamental plants and large scale crop productions Ornamental Plants • Use for decoration • Usually grown in greenhouses Ornamental Plants • Conditions needed – Types of soil – sand, organic matter – Minerals – artificial or natural fertilizers – Humidity - humid conditions better, by spraying and misting – Temperature - warm – Light - bright – Carbon dioxide – burning fuels – Water – watering plants – Pests – hand pick/pesticides Large scale crops • Includes rice, wheat, vegetables • Relies on farming methods and agricultural technology • Plant in open field Large scale crops • Light, humidity, temperature and water – cannot be controlled • Fertilizers – mostly used artificial fertilizers, machines • Pests – planes to spray pesticides over farm areas Experiment Question Experiment: Testing for starch in green leaves • What does hot water do to the leaf? – Kills the leaf to stop photosynthesis • What does the alcohol do to the leaf? – Breaks down chlorophyll – take the green colour out of the leaf • What is the original colour of iodine? – brown • What does it mean when iodine turn blueblack? – Starch is present